A number of computer screen cursor or pointing control devices have been developed in recent years which allow the user of a device to selectively position the cursor in use at any X,Y coordinate pair on a computer screen or plotting device or any such graphical display.
The central feature of previously available trackball-type mechanisms is the use of an individual sphere which is supported on bearings permitting rotation of the sphere in any direction about a central point. Motion detection devices are biased against the sphere which permit detection of sphere movement. The detected sphere movement is converted into X-axis and Y-axis components which are then utilized to reposition a cursor.
It has also been typical of this art to invert the trackball mechanism permitting the sphere to be suspended from the bottom of a housing. The sphere or trackball is then rotated by movement of the housing about a suitable surface capable of providing frictional contact with the trackball. Movement of the housing then generates movement of the trackball which is then converted into X-axis and Y-axis components utilized to reposition the cursor on the computer screen. This form of trackball control device is typically referred to as a mouse.
The trackball-type device and the mouse-type device present a number of problems to computer users. The mouse-type control device presents the drawback of requiring a surface of adequate size to permit movement of the mouse about an area sufficient to direct the cursor into all areas of the computer screen. If the space available is of insufficient size it is necessary to lift the mouse from the surface and reposition it in order to continue to move the mouse in the selected direction to achieve complete movement of the cursor or pointer across the entirety of the computer screen or plotter device. The unavailability of such sufficient surface area during travel has prompted increased use of the trackball-type device with computers.
Another type of conventional screen display control apparatus only controls adjustment by the direction in which an adjustment lever is tilted. When different kinds of functions are to be controlled, an adjustment member other than the adjustment lever must be operated. The adjustment lever must be spaced apart from the other adjustment member to a certain extent due to the restriction resulting from an operating space and design. As a result, operators must move their hands and fingers in a complicated manner to continuously control a plurality of kinds of functions.
Another approach to pointing devices is the IntelliMouse, made by Microsoft, Inc. The IntelliMouse is an inverted trackball arrangement as discussed above. In addition a clicking wheel is providing for scrolling up and down. However, the clicking wheel of the IntelliMouse is limited to a scrolling mechanism.
Technology and its resulting software development is becoming more and more sophisticated. Computer storage continues to increase, thereby permitting larger, more powerful software programs. The number of parameters has risen, and the method of selection has become more complex. Consequently, the range and capability of selection devices must simultaneously become more sophisticated.
Accordingly, what is needed is a single device capable of selection adjustment. What is further needed is a device which can accommodate more complex software programs.